Hello, once again.
What I found is when I tryed to stop the run, mlogger still working and writing some 
data, that i'm sure is not right, because frontend's are in stopped state
( for ex. every 3*frontend got 50k, mlogger showes 120k . Stop button pushed, but data 
in .mid file collect more then 150k~300k ev)
. And it continue writing until it crashes by the default waiting period 10s.